minigrep_dqy 0.1.0

    //! ## library for minigrep
    //! ### Examples
    //! 1.
    //! ```
    //! let args = 5;
    //! let anser = add_one(arg);
    //! ```

use std::{env, error::Error, fs};

pub struct Config {
    pub query: String,
    pub filename: String,
    pub case_sentitive: bool,
}

impl Config {
    pub fn new(mut args: std::env::Args) -> Result<Config, &'static str> {
        args.next();

        let query = match args.next() {
            Some(args) => args,
            None => return Err("Didn't get a query string"),
        };

        let filename = match args.next() {
            Some(args) => args,
            None => return Err("Didn't get a filename string"),
        };

        let case_sens = env::var("CASE_INSENSITIVE").is_err();

        Ok(Config { query, filename, case_sentitive: case_sens })
    }
}

pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(config.filename)?;
    
    let results = if config.case_sentitive {
        search(&config.query, &contents)
    } else {
        search_case_insensitive(&config.query, &contents)
    };

    for line in results {
        println!("{}", line);
    }

    Ok(())
}

pub fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    contents.lines()
        .filter(|line| line.contains(query))
        .collect()
}

pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    contents.lines()
        .filter(|line| line.to_lowercase().contains(&query.to_lowercase()))
        .collect()
}


#[cfg(test)]
mod tests {
    use std::vec;

    use super::*;

    #[test]
    fn one_result() {
        let query = "duct";
        let contents = "\
        Rust:
safe, fast, ductinory
        Pick three";

        assert_eq!(vec!["safe, fast, ductinory"], search(query, contents));
    }

    #[test]
    fn case_sensitive() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Duct tape.";
        assert_eq!(vec!["safe, fast, productive."], search(query, contents));
    }

    #[test]
    fn case_insensitive() {
        let query = "RUST";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.
Duct tape.";
        assert_eq!(vec!["Rust:"], search_case_insensitive(query, contents));
    }
}